Isabele Cardoso Vieira de Castro

Evaluation of the Effects of Polarized Light (λ400–200 nm) on the Healing of Third-Degree Burns in Induced Diabetic and Nondiabetic Rats

OBJECTIVE The study evaluated, by light microscopy, the repair process on third-degree burns on diabetic and nondiabetic rats, illuminated or not, with a polarized light (PL) source. BACKGROUND DATA Burns are severe injuries that result in the loss of fluid and destruction of tissue, infection, and shock that may result in death. Diabetes mellitus is a public health problem that, being uncontrolled, causes severe disturbance to the body metabolism, including on wound healing. PL sources have been shown to be effective in improving healing in many situations. MATERIALS AND METHODS Ninety male Wistar rats were divided into two groups (n=45): nondiabetic and diabetic. In one of the groups, diabetes mellitus was induced by streptozotocin. A third-degree burn, measuring 1.5×1.5 cm(2), was created in the dorsum of each animal. Phototherapy (λ400-2000 nm, 10.2 or 20.4 J/cm(2)) started immediately after burning and was repeated daily until animal death (7, 14, and 21 days). Specimens were taken, processed, and stained with H&E and Sirius red and immunomarked with cytokeratin (CK) AE1/AE3. Descriptive analysis was performed by light microscopy. RESULTS Animals subjected to phototherapy showed an acceleration of the repair, the dose of 10.2 J/cm(2) being the one that caused best results, including higher deposition of collagen, quicker inflammatory reaction, and improved revascularization. CONCLUSIONS Our results suggest that the use of PL (10.2 J/cm(2)) improves the healing of third-degree burns on both diabetic and nondiabetic animals.

Assessment of the effects of laser or LED photobiomodulation on hypothyroid rats of cutaneous wound healing: A morphometric study.

Hypothyroid has been associated to a disruption of the bodys metabolism, including the healing process. Laser and LED have been shown to be effective on improving healing in many situations, but their benefit in the improvement of healing on hypothyroidism remains unknown. The aim of this study was to assess, morphometrically, the influence of Laser (λ660nm, 24 J/cm2, 40mW, CW, spot output= 4mm2;) and LED (λ630nm ± 20, 24 J/cm2, 150mW, CW, spot output= 0.5 cm2) on the wound healing of rats with Hypothyroid. Under general anesthesia, a standard surgical wound (1cm2) was created on the dorsum of 72 male Wistar rats divided into 6 groups of 12 animals each: G1: Euthyroid; G2: Euthyroid + Laser; G3: Euthyroid + LED; G4: Hypothyroid; G5: Hypothyroid + Laser and G6: Hypothyroid + LED. Hypothyroidism was induced in rats with propylthiouracil (0.05g/100mL) administered orally for 4 weeks and maintained until the end of the experiment. Rats were irradiated after surgery each 48h then killed after 7 and 14 days. S...

Does laser phototherapy influence the proliferation of myoepithelial cells in the salivary gland of hypothyroid rats

Thyroid hormones influence both development and growth of organs and tissues and guarantee metabolic demands that interfere with the quality of digestive secretions, including those of the salivary glands. Laser phototherapy - LPT can modulate various biological phenomena and its diverse effects permit the action on different cell types. The aim of this study was to evaluate the influence of laser phototherapy on myoepithelial cells of salivary glands of hypothyroid rats. Forty-two albino Wistar rats were divided into two main groups: euthyroid (EU) and hypothyroid (HYPO). Hypothyroidism was induced using propylthiouracil (PTU) for 4weeks. Each group was divided into subgroups: control (without laser) and laser groups (Red/infrared - IR). LPT was used on the submandibular gland and was carried out using a diode laser (λ660 or λ780nm, 40mW, spot size 0.04cm2, irradiation area 1cm2, 300s, 6J/cm2 per gland, 12J/cm2 per session) and started two weeks after PTU treatment. LPT was repeated every other day for two weeks. After animal death, the glands were removed, dissected and processed for immunohistochemical analysis. It was observed an increase in the number of myoepithelial cells of hypothyroid control rats in comparison to euthyroid controls (p=0.001). Visible LPT (λ660nm) caused significant higher proliferation of myoepithelial cells in EU rats when compared to IR LPT (λ 780nm)(p≤0.001).It is concluded that, despite the LPT protocol used did not influence myoepithelial proliferation on hypothyroid rats it significantly increased the proliferation on euthyroid animals.

Assessment of LED (λ 850 ± 10 nm) phototherapy in the inflammatory process of rat’s TMJ induced by carrageenan

Temporomandibular disorders (TMD) are commonly found in the population and usually involve inflammatory processes. Previous studies have shown positive effects of LED (Light emitting diodes) phototherapies on TMD but its action and mechanism in the inflammatory infiltrate of the temporomandibular joint are still poorly understood. The aim of this study was to assess through histological analysis the effectiveness LED (10 J/cm2, λ850 nm, 100 mW, CW) on the inflammation of the temporomandibular joint of rats induced by carrageenan. Thirty animals were divided in two groups with five animals per subgroup according to the experimental times of two, three and seven days: Inflammation and Inflammation + LED phototherapy. The first irradiation was performed 24 h after induction with an interval of 48 h between sessions. After animal death, specimens were processed and stained with HE and Picrosirius. Then the samples were examined histologically. Data were statistically analyzed. The inflammation group showed mild to moderate chronic inflammatory infiltrate among the bone trabecules of the condyle. Over the time-course of the study in the LED group the condyle showed aspects of normality and absent inflammation in some specimens. In all the time-points, no statistically significant differences were found for collagen deposition in the in the condyle and disc when LED was compared to Inflammation group. LED treated groups also demonstrated a smaller number of the layers of the synovial membrane when compared to the non-irradiated groups. It was concluded that, in general, LED phototherapy resulted in a reduction of inflammatory infiltrate in the temporomandibular joint of rat.

LED phototherapy on midpalatal suture after rapid maxilla expansion: a Raman spectroscopic study

A quick bone formation after maxillary expansion would reduce treatment timeand the biomodulating effects of LED light could contribute for it. The aim of this study was to analyze the effect of LED phototherapy on the acceleration of bone formation at the midpalatal suture after maxilla expansion. Thirty rats divided into 6 groups were used on the study at 2 time points - 7 days: Control; Expansion; and Expansion + LED; and 14 days: Expansion; Expansion + LED in the first week; Expansion and LED in the first and second weeks. LED irradiation occurred at every 48 h during 2 weeks. Expansion was accomplished using a spatula and maintained with a triple helicoid of 0.020” stainless steel orthodontic wire. A LED light (λ850 ± 10nm, 150mW ± 10mW, spot of 0.5cm2, t=120 sec, SAEF of 18J/cm2) was applied in one point in the midpalatal suture immediately behind the upper incisors. Near infrared Raman spectroscopic analysis of the suture region was carried and data submitted to statistical analyzes (p≤0.05). Raman spectrum analysis demonstrated that irradiation increased hydroxyapatite in the midpalatal suture after expansion. The results of this indicate that LED irradiation; have a positive biomodulation contributing to the acceleration of bone formation in the midpalatal suture after expansion procedure.

Antimicrobial photodynamic therapy in chronic osteomyelitis induced by Staphylococcus aureus: An in vitro and in vivo study

Osteomyelitis it is an acute or chronic inflammation in the marrow spaces in the superficial or cortical bone, and associated to bacterial infection. Chronic osteomyelitis represents a major health problem due to its difficult treatment and increased morbidity. Antimicrobial photodynamic therapy (APT) by laser is a treatment based on a cytotoxic photochemical reaction in which, a bright light produced by a laser system and an active photosensitizer absorbed by cells leads an activation that induces a series of metabolic reactions that culminates a bacterial killing. The aim of this study was to assess, both in vitro and in vivo, the effect of lethal laser photosensitization on osteomyelitis. On the in vitro study a diode laser (λ660nm; 40mW; o/ = 0.4 cm2; 5 or 10 J/cm2) and 5, 10 and 15μg/mL toluidine blue (TB) were tested and the best parameter chosen for the in vivo study. The concentration of 5μg/mL was selected to perform the decontamination of infected by Staphylococcus aureus tibial bone defects in ...